June 24, 2009

Microevolution Rate Increases With Warmer Climate

A new study has found that as the climate continues to get warmer, the rate of molecular evolution in mammals could speed up as they attempt to regulate their body temperature.

A study of the same species in different climates found that the DNA of those living in warmer conditions were changing at a faster rate, researchers told BBC News.

According to the study published in the Proceedings of the Royal Society B, lead author Len Gillman from Auckland University of Technology and colleagues found the first evidence of microevolution in mammals to regulate their own body temperature.

Microevolution occurs when animal DNA mutates to result in a change that is beneficial for the species, such as disease resistance. Once the mutation has occurred, the gene is passed down to future generations.

Gillman's team studied the DNA of 130 identical pairs of mammals.

"The result was unexpected," Gillman told the BBC.

"We have previously found a similar result for plant species and other groups have seen it in marine animals. But since these are 'ectotherms' - their body temperature is controlled directly by the environment - everyone assumed that the effect was caused by climate altering their metabolic rate."

"An increase in cell division provides more opportunities for mutations in the population over a given time," Gillman told the BBC, referring to a suggested link between temperature and metabolic rate.

"This increases the probability of advantageous mutations that are selected for within the species."

"We suspected the same effect might be happening in mammals, because seasonal changes affect the animals' activity," he added.

"In warmer climates annual metabolic activity is likely to be greater, so this will lead to more total cell divisions per year in the germline."